From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753205AbZD2Q0M (ORCPT ); Wed, 29 Apr 2009 12:26:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752239AbZD2QZ5 (ORCPT ); Wed, 29 Apr 2009 12:25:57 -0400 Received: from casper.infradead.org ([85.118.1.10]:55200 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752118AbZD2QZ4 (ORCPT ); Wed, 29 Apr 2009 12:25:56 -0400 Subject: Re: Mainline kernel OLTP performance update From: Peter Zijlstra To: Andrew Morton Cc: "Styner, Douglas W" , "linux-kernel@vger.kernel.org" , "Tripathi, Sharad C" , "arjan@linux.intel.com" , "Wilcox, Matthew R" , "Kleen, Andi" , "Siddha, Suresh B" , "Ma, Chinang" , "Wang, Peter Xihong" , "Nueckel, Hubert" , "Recalde, Luis F" , "Nelson, Doug" , "Cheng, Wu-sun" , "Prickett, Terry O" , "Shunmuganathan, Rajalakshmi" , "Garg, Anil K" , "Chilukuri, Harita" , "chris.mason@oracle.com" , Ingo Molnar In-Reply-To: <20090429090706.bc5f462f.akpm@linux-foundation.org> References: <20090429002930.b786348b.akpm@linux-foundation.org> <20090429090706.bc5f462f.akpm@linux-foundation.org> Content-Type: text/plain Date: Wed, 29 Apr 2009 18:25:36 +0200 Message-Id: <1241022336.8021.573.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2009-04-29 at 09:07 -0700, Andrew Morton wrote: > On Wed, 29 Apr 2009 08:48:19 -0700 "Styner, Douglas W" wrote: > > > >-----Original Message----- > > >From: Andrew Morton [mailto:akpm@linux-foundation.org] > > >Sent: Wednesday, April 29, 2009 12:30 AM > > >To: Styner, Douglas W > > >Cc: linux-kernel@vger.kernel.org; Tripathi, Sharad C; > > >arjan@linux.intel.com; Wilcox, Matthew R; Kleen, Andi; Siddha, Suresh B; > > >Ma, Chinang; Wang, Peter Xihong; Nueckel, Hubert; Recalde, Luis F; Nelson, > > >Doug; Cheng, Wu-sun; Prickett, Terry O; Shunmuganathan, Rajalakshmi; Garg, > > >Anil K; Chilukuri, Harita; chris.mason@oracle.com > > >Subject: Re: Mainline kernel OLTP performance update > > > > > >On Tue, 28 Apr 2009 10:08:22 -0700 "Styner, Douglas W" > > > wrote: > > > > > >> Summary: Measured the mainline kernel from kernel.org (2.6.30-rc3). > > >> > > >> The regression for 2.6.30-rc3 against the baseline, 2.6.24.2 is 1.91%. > > >Oprofile reports 71.1626% user, 28.8295% system. > > >> > > >> Linux OLTP Performance summary > > >> Kernel# Speedup(x) Intr/s CtxSw/s us% sys% idle% > > >iowait% > > >> 2.6.24.2 1.000 22106 43709 75 24 0 0 > > >> 2.6.30-rc3 0.981 30645 43027 75 25 0 0 > > > > > >The main difference there is the interrupt frequency. Do we know which > > >interrupt source(s) caused this? > > > > Our analysis of the interrupts shows that rescheduling interrupts are > > up 2.2x from 2.6.24.2 --> 2.6.30-rc3. Qla2xxx interrupts are roughly > > the same. > > (top-posting repaired) > > OK, thanks. Seems odd that the rescheduling interrupt rate increased > while the context-switch rate actually fell a couple of percent. > > This came up a few weeks ago and iirc Peter was mainly involved, and I > don't believe that anything conclusive ended up happening. Peter, > could you please remind us of (and summarise) the story here? I've had several reports about the resched-ipi going in overdrive, but nobody bothered to bisect it, nor have I yet done so -- no clear ideas on why it is doing so. I'll put it somewhere higher on the todo list.